Isolated power supply system and method

Abstract

In an embodiment for supplying power to sensitive telecommunications modules in an environment rich in radiated RF emissions, the AC power line is connected to a battery charger which is alternately connected to two rechargeable batteries. A third battery is connected in power transfer relation to the telecommunications modules and to a power control module, and in turn receives power from the one of the first and second batteries which is not being charged, such active battery being completely isolated from the AC power line. The third battery insures against transients and switching noise during switchover between the first and second batteries, and the power control module monitors the supply of power via an optoelectronic isolator and connects both the first and second batteries in parallel with the third battery in the event of a power failure.

I claim as my invention: 
     
       1. In a system to be operated from an alternating current power line while providing isolation from electromagnetic interference coupled with the power line, battery charging means having charger input means for coupling with an alternating current power line and having charger output means for supplying battery charging current,   first and second rechargeable battery means for selectively supplying electric power to a utilization circuit,   radio-frequency-isolating switching means controlling connection of said charger output means with said first and second rechargeable battery means and having a first switching condition for electrically isolating said first rechargeable battery means from the charger output means during connection of the first rechargeable battery means with the utilization circuit so as to block transmission of electromagnetic interference from the alternating current power line to the first rechargeable battery means and thus to the utilization circuit via the battery charging means, while providing for supply of battery charging current from the battery charging means to the second rechargeable battery means; and having a second switching condition for electrically isolating said second rechargeable battery means from the charger output means during connection of the second rechargeable battery means with the utilization circuit so as to block transmission of electromagnetic interference from the alternating current power line to the second rechargeable battery means and thus to the utilization circuit via said battery charging means, while providing for supply of charging current from the battery charging means to the first rechargeable battery means, and   control circuit means controlling switchover of said switching means between said first and second switching condition and comprising charge storage means for maintaining the supply of power to the utilization circuit during switchover between the first and second switching conditions, said charge storage means comprising a third rechargeable battery means connected with the utilization circuit and selectively connectable with the first and second rechargeable battery means under the control of said radio-frequency-isolating switching means.     
     
     
       2. A system according to claim 1, with said first and second rechargeable battery means being of the deep discharge type with a relatively constant output voltage above five volts during delivery of at least about eighty percent of rated capacity. 
     
     
       3. A system according to claim 2 with said first, second and third rechargeable battery means having a rated output voltage of at least about twelve volts. 
     
     
       4. A system according to claim 1, with said first and second rechargeable battery means being of the lead-acid type and said third rechargeable battery means being of the nickel-cadmium type. 
     
     
       5. A system according to claim 1, with said control circuit means monitoring the alternating current power line after a power failure and controlling a resumption of the alternate charging of the battery means under selected conditions. 
     
     
       6. A power control system for controlling coupling of battery power with a utilization means, said system comprising switching means for selectively coupling a battery means with a utilization means, and processor means controlling said switching means to effect selective coupling and decoupling of the battery means with the utilization means, said processor means being controlled to actuate the switching means such that the battery means is decoupled when its operational condition may be impaired, first and second battery means for supplying power to the utilization means, said switching means in a first switching condition connecting the first battery means to the utilization means and in a second switching condition disconnecting the first battery means from the utilization means and connecting the second battery means with the utilization means, and third battery means for supplying operating power to said utilization means during actuation of said switching means between said first switching condition and said second switching condition. 
     
     
       7. A power control system according to claim 6, with said first, second and third battery means being rechargeable battery means. 
     
     
       8. A system according to claim 7, with said first and second rechargeable battery means having a relatively constant output voltage above five volts during delivery of at least about eighty percent of rated capacity. 
     
     
       9. A system according to claim 8 with said first, second and third rechargeable battery means having a rated output voltage of at least about twelve volts. 
     
     
       10. A system according to claim 7, with said first and second rechargeable battery means being of the lead-acid type and said third rechargeable battery means being of the nickel-cadmium type. 
     
     
       11. A system according to claim 6, with control circuit means comprising said processor means monitoring the alternating current power line and disabling actuation of the switching means during a power failure, and after a power failure enabling resumption of actuation of the switching means under selected conditions. 
     
     
       12. A system according to claim 6, with said switching means comprising mechanically movable electrical contact means for providing a spatial isolation gap between one of said first and second battery means, and said third battery means. 
     
     
       13. A system according to claim 12, with said electrical contact means having a dielectric-withstanding-voltage of at least about 1500 volts AC RMS between open contacts. 
     
     
       14. In a system to be operated from an alternating current power line, battery charging means having charger input means for coupling with an alternating current power line and having charger output means for supplying battery charging current, first and second rechargeable battery means for selectively supplying electric power to a utilization circuit,   switching means controlling connection of said charger output means with said first and second rechargeable battery means and having a first switching condition for electrically isolating said first rechargeable battery means from the charger output means during connection of the first rechargeable battery means with the utilization circuit, while providing for supply of battery charging current from the battery charging means to the second rechargeable battery means; and having a second switching condition for electrically isolating said second rechargeable battery means from the charger output means during connection of the second rechargeable battery means with the utilization circuit, while providing for supply of charging current from the battery charging means to the first rechargeable battery means, and   control circuit means controlling switchover of said switching means between said first and second switching condition and comprising third charge storage battery means for maintaining the supply of power to the utilization circuit during switchover between the first and second switching conditions.   
     
     
       15. A system according to claim 14, with said switching means comprising mechanically movable electrical contact means for providing a spatial isolation gap between the charger output means and the one of said battery means connected to the utilization circuit. 
     
     
       16. A system according to claim 15, with said electrical contact means having a dielectric-withstanding-voltage of at least about 1500 volts AC RMS between open contacts. 
     
     
       17. A system according to claim 14, with said charge storage battery means comprising a third rechargeable battery means. 
     
     
       18. A system according to claim 14, with said first and second rechargeable battery means providing a relatively constant output voltage above five volts during delivery of at least about eighty percent of rated capacity. 
     
     
       19. A system according to claim 14, with said first and second rechargeable battery means and said third charge storage battery means each having a rated output voltage of at least about twelve volts. 
     
     
       20. A system according to claim 14, with said first and second rechargeable battery means being of the lead-acid type and said third charge storage battery means being of the nickel-cadmium rechargeable type. 
     
     
       21. A system according to claim 14, with said control circuit means monitoring the alternating current power line after a power failure and controlling a resumption of the alternate charging of the first and second rechargeable battery means under selected conditions. 
     
     
       22. The method of operating an interference sensitive utilization means from an alternating current power line, which comprises providing plural rechargeable battery means each capable of providing operating power for the utilization means,   switching one of the battery means in circuit with the alternating current power line so as to supply charging current thereto, and switching the other of the battery means so as to be spatially isolated from the alternating current power line but so as to act as an active battery means effectively coupled with the utilization means for the transfer of stored charge thereto,   automatically switching over the roles of the respective rechargeable battery means such that in operation of the utilization means operating power can be indefinitely supplied to the utilization means while insuring against coupling of transients on the alternating current power line to the utilization means throughout such operation, and   storing charge in a further charge storage battery means connected with the utilization means, from the active one of said rechargeable battery means such that the further charge storage battery means insures against transients and switching noise during switchover of the roles of the rechargeable battery means.   
     
     
       23. A method according to claim 22, with the automatic switching of the roles of the rechargeable battery means taking place at respective time intervals within the capacity of the respective active battery means to supply maximum operating power to the utilization means.